1. Field of the Invention
The present invention relates to an efficient method of and apparatus for producing carbon fiber by making infusible and carbonizing pitch fiber which is obtained by melt-spinning petroleum-tar pitch or coal-tar pitch.
2. Description of the Prior Art
In the production of carbon fiber by melt-spinning petroleum-tar pitch or coal-tar pitch, it has been known that pitch fiber obtained is subjected to a reaction to make it infusible prior to the carbonizing thereof. The pitch fiber is made infusible as it is subjected to a take-up system in which the pitch fiber is fed and taken up around a roll, or a net conveyor system in which the pitch fiber is placed on and transferred by a net conveyor. However, in the take-up system, a high productivity cannot be obtained since the pitch fiber cannot be taken up at a high rate due to the low physical strength and ductility thereof. Moreover, it takes much time to mend pitch fiber when it is broken during the reaction according to this system. In the net conveyor system, the pitch fiber is waved in the form of net and the density of the fiber is increased by the force of gravity (their own weights). This causes the fiber to be locally damaged, and the fiber as a whole is not sufficiently oxidized.